Alloy



Patented Sept. 26, 1933 ALLOY Robert H. Leach, Fair-field, Coma, t

Handy & Harman, New York, N.

ration of New York No Drawing.

This invention relates to silver alloys and is concerned more particularly with a novel silver alloy which is of high electrical conductivity and capable of being given great hardness, and a method of hardening the alloy.

The new alloy contains a relatively large amount of silver ranging from about 50% to about 90%, beryllium varying from about 0.10% to about 2.5%, and the remainder copper, although for most commercial purposes, in which considerations of expense are important, the silver will be kept within about 65% to 75% and the beryllium will not exceed about 1.5%.

The new alloy has a wide variety of uses, as, for example, it may be used for electrode tips of welding machines, contact points, etc., an alloy which has been found highly satisfactory for electrode tips having the following approximate composition:

2@ Per cent Silver 75 Beryllium 0.6 to 0.8

Copper 24.2 to 24.4

The silver in the new alloy imparts to it the relatively high electrical conductivity while the beryllium makes the alloy capable of taking a great hardness when properly treated, an increase in the amount of beryllium present increasing the capacity of the alloy to be hardened. Ordinarily the beryllium will be used in an amount not lessthan 0.25%, although alloys with lower beryllium contents down to 0.10% or 0.15% are suiflciently hard for special purposes.

In making the new alloy, the beryllium is alloy containing silver or copper and about 10% to 12% or 13% berylliumu It is more convenient to use the beryllium in this form, since it is readily oxidized and, at the present time, is very expensive.

The hardening of the new alloy is obtained as followsf The alloy is annealed for a substantial period of time at a high temperature and then instantly quenched. It is then heated for a further substantial period at a lower temperature, the second heating giving a great increase in the hardness. While the heating in each case is a fimction of both time and temperature, I have found that desired results may be obtained by carrying on the annealing for about two hours at a temperature ranging from 1375" F. to 1400 I". At these temperatures continued for the time mentioned, substantially .complete solid solution takes place, and ii the temperature is below 1875 F., a complete eil'ect will not take place, while higher temperatures than 1400 F. are likely to cause actual melting of some of the constituents.

Upon quenching, the alloy is further heated to obtain the precipitation hardening eifect, and-I preferably employed in the form of a master.

Application August 2, 1032 Serial No. 027,305

have found that the desired hardening may be obtained by heating for about two hours at a temperature of about 625 F. The use of temperatures as high as 675 F. results in incompletehardening, but temperatures lower than 625 F. may be used although longer heating is required. For example, heating at 675 F. for about six hours gives about the same results as heating at 625 F. for two hours.

The heat treatment described imparts great hardness to the alloy, the final hardness depending on the amount of beryllium present. While the machining of the new alloys will probably not be diflicult with the modern developments in cutting tools, articles may be fabricated of the new alloy after the latter has been annealed, and may then be given a final annealing and heat treatment to obtain the desired hardness.

What I claim:

1. An alloy which consists of silver in an amount ranging from about to about 90%, beryllium varying from about 0.10% to about 2.5%, and the remainder copper.

2. An alloy which consists of silver in an amount ranging from about to about beryllium ranging from about 0.5% to about 1.5%, and the remainder copper.

3. An alloy which consists of silver in the amount of about 75%. beryllium ranging: from about 0.6% to about 0.8%, and the remainder copper. p

4. A method of. hardening alloys consisting of silver ranging from about 50% to about 90%, beryllium ranging from about 0.10% to about 2.5%, and the remainder copper, which comprises heating the alloy for a period of at least two hours at a temperature not substantially less than 1375 F. nor substantially greater than 1400 F.,

quenching the alloy, and heating the alloy for a period of not less than about two hours at a temperature of from about 575 F. to about 675 F.

5. A method of hardening alloys, consisting of silver ranging from about 50% to about 90%. beryllium ranging from about 0.10% to about 2.5%, and the remainder copper which comprisesheating the alloy for a period of at least two hours at a temperature ranging from about 1375 F. to about 1400 F., quenching the alloy, and heating the alloy for a. period of from about two to six hours at a temperature ran ing from about 575 F. to about 625 F.

ROBERT H. LEACH. 

